NoAutoRebootWithLoggedOnUsers
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
HKLM\Software\Policies\Microsoft\Windows\WindowsUpdate\AU
Stores configuration data for the policy setting No auto-restart for scheduled Automatic Updates installations.
To change the value of this entry, use the Group Policy Object Editor (Gpedit.msc). The corresponding policy is located in Administrative Templates\Windows Components\Windows Update.